1. Field of the Invention
The present invention relates to the creation and regulation of a comfortable environment within buildings and enclosures and the like, for the purpose of providing shelter from the outside climate.
2. Description of the Prior Art
Global population growth together with the urgent need to improve the standard of living of billions of peoples, has created the necessity to find an ecological means to provide controlled environments at a low cost so that comfortable habitation and work places are available for all. An affordable controlled environment technology is needed to ensure that all populations will be able to access the highest possible standard of living. At the same time it is imperative to protect the global ecology and natural environment through the development of a sustainable controlled environment technology that may be powered by renewable solar energy resources.
In the United States, building heating, ventilating, air-conditioning (known as xe2x80x9cHVACxe2x80x9d) and lighting account for approximately 40% of energy use, and they consume over 60% of the electricity produced. A substantial portion of all of the energy used in delivery of these conventional HVAC processes is derived from the combustion of fossil fuels, which results in the generation of CO2, a greenhouse gas that contributes to global warming. Additionally, air-conditioning processes are destructive to the ozone layer resulting in a potentially dangerous increase in the UV radiation reaching the surface of the earth. The generation of electrical energy is also creating problems of excessive thermal pollution. When the fuels are combusted to generate electricity by means of steam turbine power, 66% of the heat energy is immediately lost in this energy conversion step, that is the latent energy of vaporization is given up as xe2x80x9cwaste heatxe2x80x9d when the steam condenses at the condenser. This waste heat is usually absorbed by the local rivers and lakes, or is rejected to the atmosphere using costly cooling towers that consume a great quantity of water.
In the distant past, building envelopes were built with materials and methods that did not provide a practical means to maintain the interior at any specific controlled temperature, and as a result, in cold climates and winter seasons the building environment could be cold and uncomfortable. The technological solution was the development of the fireplace. Heavy masonry fireplace structures could absorb the high temperature and high rate of energy release from open flame combustion of wood and re-radiate this energy more slowly into the building. This radiative heating would then increase the surface temperature of walls, floor and roof structures in the immediate vicinity of the fireplace. There were still many hardships for building occupants because of the limitations of such methods. Over recent decades, with improved building envelope construction and the advent of central heating systems, the performance of the heating systems has so increased as to provide reasonable comfort throughout an entire building, at any time that heating many be required. Modern central furnace or boiler units have now replaced the open fireplace and air, hot water or steam is used as the working (heat exchange) fluid for the distribution and radiation of the heat; providing comfort throughout the building.
In modern times building insulation and infiltration barriers used in the building envelope have made buildings more comfortable and at the same time have reduced the expenditure of energy to achieve a controlled environment. The technology for heating the building remains based upon the use of high-grade, high temperature energy sources that distribute heat into the building using conduction and radiation from the heat exchanger units. We now also have the expectation that comfort in buildings will extend to the hot climates and seasons by means of air-conditioning systems. The approach to this technology has been modeled upon that of heating systems where mechanical units control rooms or regions of the building or the entire building may be cooled with a central mechanical system. Air-conditioning is similar to heating, in that the process uses a mechanical system powered by high-grade (electrical) or high temperature energy to generate cold temperatures at one or more heat exchangers. These cold thermal absorbers are a heat sink in relation to the building atmosphere, taking in heat by conduction and by precipitation of humidity from the air.
The state-of-art-technologies do not control humidity within buildings and tend to leave the atmosphere overly dry. This is due to the relatively large temperature difference existing at the heat exchanger device. Another deficiency is the excessive reliance upon artificial lighting due to the poor performance of windows when compared to the general insulation standards of building envelope construction today. Also, while the heat lost through windows on cold nights is extreme, the heat gain problem is just as severe. Sunlight coming into a building through windows can cause serious overheating. Because of these problems, the current recommendations for energy efficient building construction call for minimum use of windows or xe2x80x9cglazing systemxe2x80x9d, including skylights. The use of windows for xe2x80x9cpassive solar collectorsxe2x80x9d in buildings has all but been abandoned because of the very negative impact on HVAC cost that is typical of such prior solar design.
Conventional xe2x80x9cactivexe2x80x9d solar collectors are an alternate approach. These are heat collector devices that are placed on the exterior of the insulated roof or wall construction. Such systems have been generally proven to be costly, inefficient and complex. Direct conversion of solar radiation to electrical energy by photocells is, on the other hand, becoming more cost effective (for the supply of electricity in remote sites) and is inherently simple and reliable. However the complete system cost of photoelectric systems is still very high and battery storage remains a weakness.
Solar design has been approached in the same way as previous HVAC design, that is, it is expected that high temperature or high grade energy outputs would be the primary objective. This assumption is made in spite of the fact that the desired result is simply the maintenance of the building environment in the comfort zone. However, the problem is that if heat exchangers are operated at, or close to room temperature, no energy will be transferred. Without any significant temperature difference to cause conductive transfer, a heat exchanger simply will not function. Another problem is that the radiator units must have a very large area if they are to use low-grade energy (operate close to room temperature). Conversely, practical dimensioned heat exchangers (radiators) must run relatively hot or cold to have any effect. A tepid heat exchanger of conventional design will result in ineffective heating or cooling.
It is therefore an aim of the present invention to provide a technology that can reduce the use of non-renewable energy for building heating, cooling and lighting.
It is also an aim of the present invention to provide a novel method of controlling the temperature within a building envelope.
It is also an aim of the present invention to provide saving on electrical power consumption.
It is a further aim of the present invention to provide a method of controlling a building environment using low-grade energy in a thermal mass.
Therefore, in accordance with the present invention there is provided a method of controlling the temperature within a building envelope having roof and wall cavities adapted to receive an insulation material. The method comprises the steps of: a) providing a replaceable insulation material at a selected controlled supply temperature within the roof and wall cavities, and b) controlling the temperature of the insulation material while in use in the roof and wall cavities so as to maintain the insulation material temperature within a range of temperature determined as a function of a desired controlled environment temperature within the building envelope.
In accordance with a further general aspect of the present invention, there is provided a heating and cooling system for controlling the temperature within a building envelope having roof and wall cavities adapted to receive replaceable liquid foam insulator. The system comprises a liquid foam generating unit for providing liquid foam at a preselected temperature within the roof and wall cavities, a sensor for sensing the temperature of the liquid foam in the roof and wall cavities, and a control unit for actuating the liquid foam generating unit when the sensed temperature starts to fall outside of a predetermined range of temperature so that new liquid foam be generated within the roof and wall cavities at said preselected temperature in order to maintain the temperature of the liquid foam in the roof and wall cavities within the predetermined range.
In accordance with a further general aspect of the present invention, the innovative approach to solar energy utilization as provided in this invention can largely substitute solar for costly conventional energy. Additionally, there is disclosed herein a cooling process that can utilize a chilled liquid, such as water. For instance, the cooling process can tap into cold water derived from ground, lake or ocean water heat sinks or from a chilled thermal mass. Both the heating and cooling processes use low-grade, low temperature energy dynamically distributed throughout a building envelope. A special type of building envelope is used, one characteristic of which is that the roof and/or wall construction may be transparent so that, whenever available, natural daylight may be used instead of artificial lighting, thereby providing a large saving on electrical power consumption.